IS 10016 (Part 6) : 2000

Indian Standard

METHOD-SOFTESTFORPOLYBUTADIENERUBBERS
PART 6 EVALUATION OF VULCANIZATION CHARACTERISTICS OF POLYBUTADIENE RUBBERS (BR : 2)

ICS 83.060

8 BIS 2000

BUREAU

MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG NEW DELHI 110002

OF

INDIAN

STANDARDS

May 2000

Price Group 2

Rubber Sectional Committee, PCD 14

FOREWORD This Indian Standard was adopted by the Bureau of Indian Standards, after the draft linalized by the Rubber Sectional Committee had been approved by the Petroleum, Coal and Related Products Division Council. In this series methods of test for polybutadiene rubbers are given. Various other methods of test for polybutadiene rubbers are covered in following parts: Part1 Part 2 Part 4 Part5 Method of taking out test portions from sample bales Determination of ash Determination of CIS, Transand Vinyl structure Determination of gel content

The committee has decided to prepare common methods of test for synthetic rubber under SR (synthetic tubber) series and will be applicable to all types af synthetic rubbers being produced indigenously. After preparation of common methods of test, Part 1, Part 2 and Part 5 would be withdrawn. In preparation of this standard assistance has been drawn from IS0 2476 : 1996 `Rubber, butadiene (BR) Solution-polymerized types - Evaluation procedure' published by International Organization for Standardization (ISO) and ASTM D 3189 Rubber-Evaluation Solution BR (Polybutadiene Rubber), published by American Standards for Testing and Materials. In reporting the result of a test or analysis made in accordance with this standard, if the final value, observed or calculated, is to be rounded off, it shall be done in accordance with IS 2 : 1960 `Rules for rounding off numerical values (revised)`.

IS 10016 (Part 6) : 2000

Indian Standard

METHODSOFTESTFORPOLYBUTADIENERUBBERS
PART 6 EVALUATION OF VULCANIZATION CHARACTERISTICS OF POLYBUTADIENE RUBBERS (BR : 2) 1 SCOPE This standard prescribes standard materials, equipment and processing methods for evaluating vulcanization characteristics of solution-polymerized ~butadiene rubbers (BR), including oil-extended types (OEBR). 2 NORMATIVE REFEWNCES The following standards contain provisions which through reference in this text, constitute provisions of this standard. At the time of publication the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below: IS No. 1675: 1971 3400 (Part 1) : 1987 3399 : 1993 3660 (Part 3) : 1988 (Part 4) : 1988 (Part 5) : 1988 (Part 6) : 1988 (Part 7) : 1988 (Part 8) : 1999 5599 : 1999 Title Stearic acid, technical (firsr revision) Methods of test for vulcanized rubbers: Part 1 Tensile stress-strain properties (second revision) Zinc oxide for rubber industry (second revision) Methods of test for natural rubber: Determination of ash (NR:3) (second revision) Determination of total copper (NR:4) (second revision) Determination of manganese (NR:5) (second revision) Determination of rubber hydrocarbon (NR:7) (second revision) Determination of Mooney viscosity (NR: 8) Mixing and vulcanizing of rubber in standard compound (second revision) Rubber - Raw, natural and synthetic - Methods for sampling and sample preparation (firsr revision) Benzothiazyl-2-cyclohexyl sulphenamide (first revision) High abrasion furnace (HAP) carbon black (first revision) Sulphur for rubber industry (fir.rl revision) Methods of test for synthetic rubber: (Part 2) : 1989 Measurement of vulcanization characteristics with oscillating disc curemeter (SR:2) (Part 3) : 1993 Determination of Mooney viscosity (Part 4) : 1993 Determination of volatile matter Rubber standard temperature, 13867 : 1993 humidities and times for the conditioning and testing of test pieces 3 TEST RECIPE FOR EVALUATION OF VULCANIZATION CHARACTERISTICS 11720 3.1 Standard Test Formula The standard test formula is given below:
No.

Sl

Material

Parts by Mass Non-oil Oil Extended Extended

i>

Butadiene rubber (BR)

100.00 3.00 60.00 2.00 15.00

100.00 3.00 60.00 2.00 -

ii) Zinc oxide (see IS 3399) iii) Oil furnace black (HAP)" (No. 330) (see IS 7497) iv) Stearic acid (see IS 1675) v) Petroleum oil (naphthenic)*' (see ASTM Type 103) vi) Sulphur (see IS 885 1) vii) CBS (see IS 7069) or TBBS3' (for method D) (min) viii) Calculated density, mg/m3

1.50 0.90

1.50 0.90

1.11

1.14 to 1.16 4,

`) The current Industry Reference Black may be used in place of HAF carbon black but this may give slightly different results. *) ASTM Type 103 oil has the following characteristics: Kinematic viscosity at 100°C, 16.8 f 1.2 mm% Viscosity gravity constant, 0.889 % 0.002 The Viscosity Gravity Constant (VGC) is calculated from the Saybolt Universal viscosity at 37.8"C and the relative density at 15.5/15.5"C. Use the following equation to calculate the VGC from the measured properties:

7069 : 1986 7497 : 1985 8851 : 1994

IS 10016 (Part 6) : 2000 vGc= lOd-1.0752 logtc (v-38)
IO-logtu (v-38) where d = relative density at 15.5/15.5°C; v = Saybolt Universal Viscosity at 7.8"C. `) N-ter-butyL2benzothiazile Reference No. 384. sulphenamide as per Material

Duration Cumulative (fin) (tin)

c) d) e)

`) Based on 37.5 percent oil-extended BR.

3.2 Procedure 3.2.1 Equipment and Procedure

0

Equipment and procedure for the preparation, mixing and vulcanization shall be in accordance with different parts of IS 3660 (Part 8) wherever applicable.
NOTE - Details of a suitable internal mixer are given in Annex A.

g)

Allow the batch to mix. 3.0 3.5 Raise the ram and clean the 0.5 4.0 mixer throat and the top of the ram. Lower the ram. Discharge the batch at a 2.0 6.0 temperature of 170°C or after a total time of 6 min. whichever occurs first. Immediately pass the batch three times through a laboratory mill with a mill opening of 5.0 mm and a temperature of 50 f 5°C. Check, weigh the batch. If the batch weight differs from the theoretical value by more than 0.5 percent, discard the batch. Rest the batch for at least 30 minutes and up to 24 h.

3.2.2 Mixing Procedure The following four mixing procedures are specified:
Method A Method B

Stage 2 - Final mixing procedure Duration Cumulative Wn) Wn)

Cool the internal mixer to a 0 0 temperature of 40 -c 5°C with full cooling water on the rotors. Method C Start the motor and raise the ram. Method D 0.5 b) Leave the cooling water on and 0.5 NOTE - These procedures may give different results. the steam off. Roll all the The mill handling of solution butadiene rubbers is more sulphur and the CBS into onedifficult than for other rubbers and mixing is best accomplished half of the -masterbatch and by using an internal mixer. Because of the difficulty of mill charge into the mixer. Add the mixing butadiene rubber, it is recommended that one of the remaining portion of the internal mixer procedures (methods A, B or D) be used where such equipment is available. With some types of butadiene masterbatch. Lower the ram: rubber it is not possible to get a satisfactory mix using the mill 3.0 cl Allow the batch to mix until a 2.5 mixing procedure. temperature of 110°C or a total time of 3 min is reached, 3.2.2.1 Method A whichever occurs first. Internal Mixer for initial and final mixing d) Immediately pass the batch through a laboratory mill with a mill opening set at 0.3 mm and at a Stage 1 - Initial mixing procedure temperature of 50 f 5°C. Duration Cumu- e) Pass the rolled batch endwise through the rolls (min) lative six times. (min) f) Sheet the batch to approximately 6 mm and 0 0 check, weigh. Remove sufficient sample for a) Adjust the temperature, speed and ram pressure of the internal curemeter testing, if required. mixer to achieve the condition g) Sheet the batch to approximately 2.2 mm for outlined in 3.2.2.1(e). Close the preparing test slabs or to the appropriate discharge gate, start the rotor thickness for preparing ring specimen. and raise the ram. 3.2.2.2 Method B 0.5 b) Charge one-half of the tubber, the 0.5 Internal mixer for initial and mill for final mixing zinc oxide, the carbon black, the oil (omit from Formula 2 for OEBR), Stage 1 - Initial mixing procedure the stearic acid and the balance of the rubber. Lower the ram. 2

Internal mixer for initial and final mixing; Internal mixer for initial and mill for final mixing; Mill mixing; and Miniature internal mixing.

a)

IS10016(Part 6):2000
Prepare the initial mix in accordance with procedure outlined in 33.2.1. (Stage 1)
Stage 2 - Final mill mixing procedure
Dumtion (rw ClUnlJ-

* yzg

Adjust the mass of all material (that is masterbatch, sulphur and CBS) to give a final batch mass of four times the formula mass,
NOTE - AU null openings should be adjusted to maintain a good rolling bank at the nip of the rolls mixing. If this is not obtained with the settings specifmd hereunder, small adjustments to mill openings may be necemary:
Dumdoll Cumu-

h)
c

lathe

(mW a)

Wn)
8

b)

a
d)

e)

4

Set and maintain the mill roll 1.0 1.0 temperature at 40 * 5°C and the mill opening at 1.5 mm. Band the masterbatch and band round the front roll. Add the sulphur and the CBS slowly to 1.0 2.0 the batch. Make six 3/4 cuts from each side. 1.5 3.5 Cut the batch from the mill. Set tbe mill 15 5.0 opening to 0.8 nun and -pass the mEed . batch end-wise through the rolls six times. Sheet the batch to approximately 6 mm and check, weigh. Remove sufficient sample for curemeter testing, if tquhed. If the weight differs ttpre than 0.5 percent from the theoretical value, discard the batch. Sheet the batch to approximately 2.2 mm for preparing test slabs or to the appropriate thickness for pmparing specimens. Cool the compound on a flat drymetal surface at 23 f 3°C for 16handRHSUpercent.

Add the oil (omit from Formula 2 for 8 to 10 26 to 31 OEBR) very slowly drop by drop. 2 Add the sulphur and the CBS. 28to33 Make six successive 314 cuts from each 2 3oto35 side. Cut the batch from the mill, set the mill 2 32to37 opening to 0.8 mm and pass the rolled batch end-wise through the rolls six times. L Sheet the batch to approximately 6 mm and check, weigh the batch. Remove sufficient sample for curemeter testing if nquired. The weight should not differ more than 0.5 percent from the theoretical value, if more discard the batch. Sheet the batch to approximately 2.2 mm for preparing teat slabs or to the appropriate thickness for preparing ring specimens. Cool the compound on a flat dry metal surface at 23 t 3°C for l-24 h and RH <- 55 percent. NOTE - It is sometimes easier and mote practical to combine steps 3.2.2.3(c) and 3.2.2.3(d) above, either by premixing the oil and black together-and then adding the oiled black diitiy to the nrbbcr on the miB as described in 4.2.23(c) and thus omitting 4.2.23(d) or by adding carbon black and oil nltcmately.

3.2.2.4 Method D - Miniature Internal Mixer (MIM) procedure a) For general mixing procedure. b) Mix with the head temperature of the miniature internal mixer maintained at 60 i 3°C and the rotor speed set at 6.3 *to 63 rpm. c) Prepare the rubber by passing it through a mill one time with the temperature set at 40 H"C and an opening that would give approximately 5 mm thick sheet. Cut the sheet into strips that are approximately 25 mm wide. Dura- Cumution lative (fin) (fin) Charge the mixing chamber with 0.0 0.0 the rubber strips lower the ram, and start timer. 0.5 Masticate the rubber. 0.5 Raise the ram, add zinc oxide, 1.0 1.5 sulphur, stearic acid and TBBS that have previously been blended taking cam to avoid any loss. 2.5 Add portions of carbon black 1 and oil alternately sweep the orifice and lower the ram. Allow the batch to mix, raising 6.5 9.0 the ram momentarily to sweep
down if necessary.

3.2.23 Met&&C - Mill mixing procedure
The standard laboratory batch mass, in grams, shah be based on four times the formula mass. Adjust the mill roll cooling conditions to maintain a temperature of 35 f 5°C throughout the mixing operations.
NOTES 1 Methods A and B, which give better diipension of the ingredients. are to be preferred if an internal mixer is available. 2 All mill openings should be adjusted to maintain a good rolling bank at the nip of the rolls during mixing. If this is not obtained with the settings specitied hemunder, small adjustments to mill openings may be necessary:
Dum!ion

a) b)

Onin) a)
b) c) Band the rubber with the mill opening 1 setat 1.3 mm. Add the zinc oxide and the stearic acid 2 evenly acmss the tolls. Make two_3/4 cuts from each side. Add the carbon black evenly across the lSto18 rolls at a uniform rate. When about half the black has been incorporated. open the roils to 1.8 mm and then add the remainder of the black. Make hvo 314 cuts from each side, allowing 30 s between each cut. Be certain to add the black that has dropped into the miil pan.

cumulative Wn)

c)

1 3 18to21

4 e)

0 Turn off the motor, raise the ram, remove the mixing chamber, and discharge the batch. Record the maximum batch temperature indicated if de&d.

3

IS 10016 (Part 6) : 2000 g) Pass the batch through a mill at 40 f 5°C and 0.5 mm opening once then twice at 3 mm opening. h) Check the batch mass and record. If it differs from the theoretical value by more than 0.5 percent, discard the batch. 4 CONDITIONING OF COMPOUNDS Conditioning all batches produced by methods A, B, C or D at a standard laboratory temperature for 1 to 24 h after mixing and prior to vulcanizing as per IS 13867. 5 EVALUATION OF WLCANIZATION cHARAcTERISTIcs 5.1 Evaluation According to. Stress-Strain Properties 5.1.1 Vulcanize sheets at I'45'C for 25, 35 and 50 e min. Alternatively, vulcanize sheet at 150°C for 20,30 and 50 min. The recommended cure time for the miniature internal mixture compound if 35 min at 145°C. 5.1.2 Condition the vulcan&d sheets for 16 to 96 h at a standard laboratory temperature and humidity defined in IS 13867. 5.13 Measure the stress-strain properties in accordance with IS 3400 (Part 1). 5.2 Evaluation According to Oscillating Disc Curemeter Test Measure the following standard test parameters: ML, MH, fsl, I, (50) and r'c = (90) in accordance with IS 11720 (Part 2). using the following test conditions: Oscillation frequency
: 1.7 Hz (100 cycles/

min) Amplitude of oscillation : 1°C arc Selectivity. : To be selected to give at least 75 percent full scale deflection
NOTE - w&h some plbbex, 75 percent may not be attainable.

Die temperature Pre-heat time

: 160* 1°C : None

ANNEX A . (Clause 3.2.1)
INTERNAL,MIXER A-l The internal mixer should have .a nominal capacity of approximately 1000 CC. A-2 The rotor speed(s), ram pressure and coolant
' flow of the internal mixer should be such that the

A-3 The batch size should be the nominal capacity of the internal mixer measured in cubic centimetres, multiplied by the density (+ 0, - 10 percent).
NOTE- If an old or worn internal mixer is used. the batch

conditions specified in 3.2.2.1(e), 3.2.2.2(c) and 3.233(e) will be accomplished.

muss should be incmased accordingly.

Bureau of Indian Standards BIS is a statutory institution established under the Bureau of Indian Standards Act, 1986 to promote harmonious development of the activities of stardardization, marking and quality certification of goods and attending to connected matters in the country. Copyright BIS has the copyright of all its publications. No part of these publications may be reproduced in any form without the prior permission in writing of BIS. This does not preclude the free use, in the course of` implementing the standard, of necessary details, such as symbols and sizes, type or grade designations. Enquiries relating to copyright be addressed to the Director (Publication), BIS Review of Indian Standards Amendments are issued to standards as the need arises on the basis of comments. Standards are also reviewed periodically; a standard along with amendments is reaffirmed when such review indicates that no changes are needed; if the review indicates that changes are needed, it is taken up for revision. Users of Indian Standards should ascertain that they are in possession of the latest amendments or edition by referring to the latest issue of `BIS Handbook' and `Standards: Monthly Additions'. This Indian Standard,has been developed from Dot: No. PCD 14 (1058). Amendments Issued Since Publication Amend No. Date of Issue Text Affected

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